1. Field of the Invention
The present invention relates generally to the art of making food chip products, and more specifically to a method and apparatus for making fat-free potato chips using a combination of hot air impingement and microwave/hot air drying.
2. Description of the Related Art
Food chip products such as potato chips and tortilla chips are typically produced using hot oil. The manufacturer fries the potato slices or tortilla slices in hot oil, which reduces the moisture content of the slices. Subjecting these food products to hot oil results in a final chip having a fat content of greater than 35 per cent by weight.
Today's health conscious consumer is looking for a low fat alternative to the traditional fried chip, and preferably a completely fat free product having minimal taste differences from the fried product. Different methods and means of preparing a fat-free chip have been employed in the past, including subjecting the chip to various processes which involve, at some stage of preparation, the application of a reduced amount of oil (see, e.g., Dreher et al., U.S. Pat. No. 4,756,916, or Fazzolare et al., U.S. Pat. No. 4,873,093), or subjecting the chips to a hot air impingement oven (see, e.g., Zussman, U.S. Pat. No. 5,370,898) or subjecting the chips to one or more microwave processes (see, e.g., Kloos, U.S. Pat. No. 4,906,483).
These prior art methods and devices each have their respective drawbacks. Subjecting chips to oil during processing increases the fat content of the final chip, which is undesirable. Exposing the chip to conventional fluid bed impingement ovens does not guarantee that the moisture content for all slices will be at a proper level and generally results in at least part of the final yield containing a lower quality product, i.e. product having excessive moisture or burned product, which must then be reheated or discarded. In particular, impingement ovens have been known to overcook or burn over 60 per cent of the food. The only means available to reduce or eliminate this overcooking is to sacrifice production rates by reducing air temperatures, the amount of potatoes used in the process, or the amount of time the product resides in the oven. Utilizing any one of these steps tends to case harden the final chip, as the slow removal of water prevents the puffing which is desirable in chips.
Subjecting the chip to microwaving generally works with a limited amount of product, and maintaining a high quality over a large batch of potato slices can be difficult.
It is therefore an object of the current invention to provide a method and apparatus for producing fat-free chip products, i.e. chip products having a significantly reduced oil content.
It is also an object of the current invention to provide a method and apparatus for preparing fat-free snack chips which causes an increased usable product yield in a relatively short amount of time over past chip making procedures.
It is another object of the current invention to provide a method and apparatus for preparing fat-free snack chips whereby consistent moisture levels are obtained without overcooking and without imparting a burned flavor to the final product, and at the same time maintains the typical light color preferred by consumers.
It is yet a further object of the current invention to provide a method and apparatus for preparing fat-free snack chips whereby the final product does not exhibit starch gelatinization problems typically associated with excessive microwave application.